Heat from different binned LuxVs?

I switched out a VX1S in a Quicksilver V (luxV vari-brite) with a WX0S. And the light is brighter (Very bright!) and whiter, but it also runs cooler....

It used to get quite hot, but now it runs pretty cool. I've used arctic silver, polished the mating aluminum surfaces and everything seems to be ok.
Even when touching the metal on the star-heatsink it isn't hot, just warm.

The light supplies 6.05-6.10V to the led with both bins and should be running the LuxV well. It did put out about 80 lumens on Quickbeams test and my guesstimate of the light before modding would be about that.
Now it puts out a lot more light, but it also seems to run a lot cooler....

Sverre

Not 100% sure, but normally a S vf. will run cooler than a T vf. because it takes less energy to power it when running at the same current which mean less heat aswell.
S vf. are ranged form 5.91V-6.39V, so your original VX1S could be on the high end of the scale or you got one efficient WXOS!

I've tested the temperature of the WX0S star using an IR thermometer and it stays in the low 30s (deg C) even after running a few minutes on high.

My HDS gets warm to the touch in less time so I'm wondering; have I gotten a super efficient monster LuxV or could there be some other reason?

The Lux is being fed 6.05-6.15V on high and the old S-bin got really warm after a couple of minutes while giving out less light.
I think the old led only got 6.0V from the same light so there might be several things contributing here....
Being a newbie I'm a loss as to why this is happening..

Sverre